Lysosomotropic agents as HCV entry inhibitors

Ashfaq, Usman Ali; Javed, Tariq; Rehman, Sidra; Nawaz, Zafar; Riazuddin, Sheikh

doi:10.1186/1743-422x-8-163

Cited by 57 publications

(44 citation statements)

References 27 publications

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“…To strengthen our hypothesis, we next treated cells with chloroquine (CQ), a lysosomotropic weak base that inhibits acidification of lysosomes and endosomes. CQ is a widely used molecule for the treatment of malaria and exerts inhibitory effects against several RNA viruses, including HCV (15,70,71). As shown in Fig.…”

Section: Monensin Inhibits Hcv Infectionmentioning

confidence: 99%

New Insights into the Understanding of Hepatitis C Virus Entry and Cell-to-Cell Transmission by Using the Ionophore Monensin A

Fénéant

Potel

François³

et al. 2015

J Virol

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In our study, we characterized the effect of monensin, an ionophore that is known to raise the intracellular pH, on the hepatitis C virus (HCV) life cycle. We showed that monensin inhibits HCV entry in a pangenotypic and dose-dependent manner. Monensin induces an alkalization of intracellular organelles, leading to an inhibition of the fusion step between viral and cellular membranes. Interestingly, we demonstrated that HCV cell-to-cell transmission is dependent on the vesicular pH. Using the selective pressure of monensin, we selected a monensin-resistant virus which has evolved to use a new entry route that is partially pH and clathrin independent. Characterization of this mutant led to the identification of two mutations in envelope proteins, the Y297H mutation in E1 and the I399T mutation in hypervariable region 1 (HVR1) of E2, which confer resistance to monensin and thus allow HCV to use a pH-independent entry route. Interestingly, the I399T mutation introduces an N-glycosylation site within HVR1 and increases the density of virions and their sensitivity to neutralization with anti-apolipoprotein E (anti-ApoE) antibodies, suggesting that this mutation likely induces conformational changes in HVR1 that in turn modulate the association with ApoE. Strikingly, the I399T mutation dramatically reduces HCV cell-to-cell spread. In summary, we identified a mutation in HVR1 that overcomes the vesicular pH dependence, modifies the biophysical properties of particles, and drastically reduces cellto-cell transmission, indicating that the regulation by HVR1 of particle association with ApoE might control the pH dependence of cell-free and cell-to-cell transmission. Thus, HVR1 and ApoE are critical regulators of HCV propagation. IMPORTANCEAlthough several cell surface proteins have been identified as entry factors for hepatitis C virus (HCV), the precise mechanisms regulating its transmission to hepatic cells are still unclear. In our study, we used monensin A, an ionophore that is known to raise the intracellular pH, and demonstrated that cell-free and cell-to-cell transmission pathways are both pH-dependent processes. We generated monensin-resistant viruses that displayed different entry routes and biophysical properties. Thanks to these mutants, we highlighted the importance of hypervariable region 1 (HVR1) of the E2 envelope protein for the association of particles with apolipoprotein E, which in turn might control the pH dependency of cell-free and cell-to-cell transmission. H epatitis C virus (HCV) infection is a global public health problem affecting over 130 million individuals worldwide.Chronic HCV infection can result in liver cirrhosis and hepatocellular carcinoma (1). While previous interferon (IFN)-based therapies have been limited by drug resistance and marked toxicity (2), the recently clinically licensed direct-acting antivirals are expected to cure the large majority of infected patients without major adverse effects (3). Nevertheless, several challenges remain: high costs limit access to therapy ...

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Section: Monensin Inhibits Hcv Infectionmentioning

confidence: 99%

New Insights into the Understanding of Hepatitis C Virus Entry and Cell-to-Cell Transmission by Using the Ionophore Monensin A

Fénéant

Potel

François³

et al. 2015

J Virol

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“…Recently, we identified ferroquine (FQ), a ferrocenic analog of chloroquine (CQ) (15) as a new inhibitor of HCV entry. Furthermore, CQ has also been shown to inhibit several steps of the HCV life cycle (13,16,17). We were therefore interested to test other derivatives of 4-aminoquinoline-based molecules for their anti-HCV activity.…”

Section: H Epatitis C Virus (Hcv) Infection Remains a Global Epidemicmentioning

confidence: 99%

Identification of a New Benzimidazole Derivative as an Antiviral against Hepatitis C Virus

Vausselin

Séron

Lavie

et al. 2016

J Virol

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Aminoquinolines and piperazines, linked or not, have been used successfully to treat malaria, and some molecules of this family also exhibit antiviral properties. Here we tested several derivatives of 4-aminoquinolines and piperazines for their activity against hepatitis C virus (HCV). We screened 11 molecules from three different families of compounds, and we identified anti-HCV activity in cell culture for six of them. Of these, we selected a compound (B5) that is currently ending clinical phase I evaluation for neurodegenerative diseases. In hepatoma cells, B5 inhibited HCV infection in a pangenotypic and dose-dependent manner, and its antiviral activity was confirmed in primary hepatocytes. B5 also inhibited infection by pseudoparticles expressing HCV envelope glycoproteins E1 and E2, and we demonstrated that it affects a postattachment stage of the entry step. Virus with resistance to B5 was selected by sequential passage in the presence of the drug, and reverse genetics experiments indicated that resistance was conferred mainly by a single mutation in the putative fusion peptide of E1 envelope glycoprotein (F291I). Furthermore, analyses of the effects of other closely related compounds on the B5-resistant mutant suggest that B5 shares a mode of action with other 4-aminoquinoline-based molecules. Finally, mice with humanized liver that were treated with B5 showed a delay in the kinetics of the viral infection. In conclusion, B5 is a novel interesting anti-HCV molecule that could be used to decipher the early steps of the HCV life cycle. IMPORTANCEIn the last 4 years, HCV therapy has been profoundly improved with the approval of direct-acting antivirals in clinical practice. Nevertheless, the high costs of these drugs limit access to therapy in most countries. The present study reports the identification and characterization of a compound (B5) that inhibits HCV propagation in cell culture and is currently ending clinical phase I evaluation for neurodegenerative diseases. This molecule inhibits the HCV life cycle by blocking virus entry. Interestingly, after selection of drug-resistant virus, a resistance mutation in the putative fusion peptide of E1 envelope glycoprotein was identified, indicating that B5 could be used to further investigate the fusion mechanism. Furthermore, mice with humanized liver treated with B5 showed a delay in the kinetics of the viral infection. In conclusion, B5 is a novel interesting anti-HCV molecule that could be used to decipher the early steps of the HCV life cycle.

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“…These include bafilomycin A1 and concanamycin A, which are inhibitors of vacuolar H+-ATPases [130]. Weak bases such as chloroquine and ammonium chloride were also found to inhibit the low pH-dependent conformational change required for the viral fusion, based on their ability to penetrate lysosomes and increase the pH [131]. Finally, dUY11, one of the rigid amphipathic fusion inhibitors (RAFIs), was suggested to inhibit HCV entry by interacting with the hydrophobic structures in virions and preventing the formation of negative curvature required for viral fusion [132].…”

Section: Inhibition Of Clathrin-mediated Endocytosis and Viral Fusionmentioning

confidence: 99%

Strategies to Preclude Hepatitis C Virus Entry

Burnouf¹,

Lin²

2017

Advances in Treatment of Hepatitis C and B

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Without a preventive vaccine, hepatitis C virus (HCV) remains an important pathogen worldwide with millions of carriers at risk of end-stage liver diseases. Despite the introduction of novel direct-acting antivirals (DAAs), resistance problems, challenges with the difficult-to-treat populations and high costs limit the widespread application of these drugs. Antivirals with alternative mechanism(s) of action, such as by restricting viral entry or cell-to-cell spread, could help expand the scope of antiviral strategies for the management of hepatitis C. Transfusion-associated HCV infection remains another issue in endemic and resource-limited areas around the world. This chapter describes some of the latest developments in antiviral strategies to preclude HCV entry, such as through monoclonal antibodies and small molecules, as well as measures to enhance the safety of therapeutic plasma products in blood transfusion.

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Lysosomotropic agents as HCV entry inhibitors

Cited by 57 publications

References 27 publications

New Insights into the Understanding of Hepatitis C Virus Entry and Cell-to-Cell Transmission by Using the Ionophore Monensin A

New Insights into the Understanding of Hepatitis C Virus Entry and Cell-to-Cell Transmission by Using the Ionophore Monensin A

Identification of a New Benzimidazole Derivative as an Antiviral against Hepatitis C Virus

Strategies to Preclude Hepatitis C Virus Entry

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